Plurale Tantum is Latin for, “pural only.” It is a noun that only has a plural form and doesn’t have a singular form.

Here are some examples:

scissors
slacks (referring to pants)
glasses (referring to eyewear)
shenanigans
cahoots
amends (as in “making amends”)
thanks
goggles
smithereens
suds
trousers
jitters
riches